He’s only an “issue” in QM because huge numbers of people have for some inexplicable reason started picking him in masses, so he often appears even on both teams.
And most of those people don’t understand Abathur enough to play him successfully.
In SL you can simply ban him.
(I don’t know why this change in QM happened, in earlier years he was somewhat rare even in QM, appearing in ~10% of them?)
I checked from patch 2.53.1 onwards and he is actually the second most played QM hero now after Li-Ming.
That is absurd considering the skill level required to play him optimally.